Precipitation and streamflow changes in China: Changing patterns, causes and implications

Extensive investigation was done on the changes in precipitation and streamflow in both space and time across China based on monthly precipitation data from 590 rainfall stations and on monthly streamflow data from 382 hydrological stations covering 1960-2000. Causes behind the precipitation changes were studied based on NCAR/NCEP reanalysis dataset. Influences of agricultural irrigation on availability and variability of water resources and related implications were also discussed. The results indicate that: (1) decreasing precipitation is found mainly in the regions between 105 degrees E and 115 degrees E and in the northeast China. Scarce precipitation is observed mainly in spring and autumn and winter seems to be wetter; (2) alterations of the East Asian monsoon activities should be the causes behind the spatial patterns of precipitation changes. Large-scale circulation of water vapor flux can well explain the spatial distribution of precipitation changes in China; (3) streamflow changes are mainly the results of precipitation changes. Agricultural irrigation heavily influences the variability and availability of water resources. Increasing water consumption due to booming socio-economy and fast growing population will further deteriorate the water status of China. In this sense, scientific and effective water resource management and advanced agricultural technology are urgently called for to ensure the sustainable socio-economy and social stability of China. (C) 2011 Elsevier B.V. All rights reserved.